From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Arend Van Spriel <arend.vanspriel@broadcom.com>,
Felix Fietkau <nbd@nbd.name>,
linux-wireless@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH 5/5] mac80211: set NETIF_F_LLTX when using intermediate tx queues
Date: Wed, 17 Apr 2019 10:17:09 +0100 [thread overview]
Message-ID: <87tvexrnxm.fsf@toke.dk> (raw)
In-Reply-To: <20190417033834.ep6t7r6ttvjek5g7@gondor.apana.org.au>
Herbert Xu <herbert@gondor.apana.org.au> writes:
> On Tue, Apr 16, 2019 at 02:18:36PM +0100, Toke Høiland-Jørgensen wrote:
>>
>> > The congestion control happens at two levels. You are right that the
>> > socket buffer acts as one limit. However, other applications may also
>> > rely on the TX queue being full as the throttle (by setting a
>> > sufficiently large socket buffer size).
>>
>> Do you happen to have an example of an application that does this that
>> could be used for testing? :)
>
> Have a look at
>
> commit 6ce9e7b5fe3195d1ae6e3a0753d4ddcac5cd699e
> Author: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Wed Sep 2 18:05:33 2009 -0700
>
> ip: Report qdisc packet drops
>
> You should be able to do a UDP flood while setting IP_RECVERR to
> detect the packet drop due to a full queue which AFAICS will never
> happen with the current mac80211 setup.
Also, looking at udp.c, it seems it uses net_xmit_errno() - which means
that returning NET_XMIT_CN has the same effect as NET_XMIT_SUCCESS when
propagated back to userspace? Which would kinda defeat the point of
going to the trouble of propagating up the return code (the mac80211
queue will never drop the most recently enqueued packet)...
-Toke
next prev parent reply other threads:[~2019-04-17 9:26 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-16 17:06 [PATCH 1/5] mac80211: mesh: drop redundant rcu_read_lock/unlock calls Felix Fietkau
2019-03-16 17:06 ` [PATCH 2/5] mac80211: fix memory accounting with A-MSDU aggregation Felix Fietkau
2019-03-16 18:12 ` Toke Høiland-Jørgensen
2019-03-16 17:06 ` [PATCH 3/5] mac80211: calculate hash for fq without holding fq->lock in itxq enqueue Felix Fietkau
2019-03-16 18:13 ` Toke Høiland-Jørgensen
2019-03-16 17:06 ` [PATCH 4/5] mac80211: run late dequeue late tx handlers without holding fq->lock Felix Fietkau
2019-03-16 18:13 ` Toke Høiland-Jørgensen
2022-12-05 9:46 ` Wen Gong
2022-12-07 6:30 ` Wen Gong
2022-12-12 8:31 ` Wen Gong
2019-03-16 17:06 ` [PATCH 5/5] mac80211: set NETIF_F_LLTX when using intermediate tx queues Felix Fietkau
2019-03-16 18:14 ` Toke Høiland-Jørgensen
2019-04-14 9:44 ` Arend Van Spriel
2019-04-14 11:19 ` Felix Fietkau
2019-04-14 12:34 ` Arend Van Spriel
2019-04-16 7:34 ` Arend Van Spriel
2019-04-16 7:44 ` Herbert Xu
2019-04-16 8:04 ` Arend Van Spriel
2019-04-16 8:36 ` Herbert Xu
2019-04-16 8:37 ` Johannes Berg
2019-04-16 9:17 ` Arend Van Spriel
2019-04-16 9:29 ` Herbert Xu
2019-04-16 9:33 ` Toke Høiland-Jørgensen
2019-04-16 9:33 ` Johannes Berg
2019-04-16 9:37 ` Herbert Xu
2019-04-16 9:39 ` Johannes Berg
2019-04-16 10:02 ` Toke Høiland-Jørgensen
2019-04-17 2:11 ` Herbert Xu
2019-04-17 8:28 ` Toke Høiland-Jørgensen
2019-04-16 13:13 ` Herbert Xu
2019-04-16 13:18 ` Toke Høiland-Jørgensen
2019-04-17 3:38 ` Herbert Xu
2019-04-17 9:09 ` Toke Høiland-Jørgensen
2019-04-17 9:16 ` Arend Van Spriel
2019-04-17 9:17 ` Toke Høiland-Jørgensen [this message]
2019-04-23 12:41 ` Johannes Berg
2019-04-25 8:35 ` Herbert Xu
2019-04-25 8:39 ` Johannes Berg
2019-04-25 8:44 ` Herbert Xu
2019-04-25 8:49 ` Johannes Berg
2019-04-16 19:13 ` Johannes Berg
2019-04-17 2:13 ` Herbert Xu
2019-04-16 9:38 ` Toke Høiland-Jørgensen
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